The low utilization rate of electrochemical energy storage power stations is the main challenge facing the current industry. The root of this problem is partly due to the uneven level of equipment performance, which is specifically reflected in the obvious differences in the availability level of energy storage equipment, charging and discharging energy and efficiency. There are significant differences. At the same time, its transient support capacity has not reached the expected standards, and some projects have difficulty in meeting the requirements of power grid companies such as fault ride-through and operational adaptability.

In the early stages of the industry’s development, due to the industry’s immaturity, there was a large gap between the theoretical performance and actual performance of energy storage equipment, and various performance “false labels and false highs” emerged one after another. The energy storage system “fails” when called upon by the power grid, and often fails to achieve the expected results. For example, the continuous charging and discharging energy issued by the dispatcher cannot be achieved, and the equipment reliability is poor. In addition, there have been many safety accidents at home and abroad. Compared with traditional pumped storage and thermal power units, new energy storage was once regarded as an “unreliable regulatory resource”. In the early days, power companies in some regions had a certain resistance to calling on energy storage.

However, with the increase in the proportion of new energy and the improvement of the "status" of energy storage, the scale of energy storage power stations continues to grow rapidly, and more and more regions regard energy storage as an important regulatory resource in the future. But how energy storage can "live up to the trust", give full play to its multiple support and regulatory capabilities, and realize its own value has become the focus of industry attention.

New energy storage is the main market member of future electricity. It can participate in transactions in the medium- and long-term markets, electricity spot markets, ancillary service markets, etc. under the electricity market. It can perform its functions and obtain profits by accepting grid dispatch or "self-" charging and discharging in the electricity spot market.

The National Energy Administration recently issued a policy document, "Basic Rules for Electricity Market Registration", which clarifies that new energy storage can be used as an operating entity, but also puts forward the basic conditions for its participation in the electricity market, namely, signing a grid-connected dispatching agreement with the power grid company, connecting to the power dispatching automation system, and meeting the corresponding technical conditions such as maximum charging and discharging power, maximum regulation capacity and continuous charging and discharging time.

Improving the grid-connected performance of energy storage power stations is the basis for achieving efficient regulation and support of the power grid, and grid-connected testing is also the main means to measure its grid-connected performance level.

After the electrochemical energy storage power station is connected to the grid, a third-party testing agency will conduct grid connection testing, and generally complete grid connection commissioning and acceptance work within 3 months after grid connection to ensure that the electrochemical energy storage power station meets the requirements for safe and stable operation of the grid after being connected to the grid, and to ensure the support and regulation capabilities of the grid.

It is worth noting that the revised national standard "Technical Regulations for the Connection of Electrochemical Energy Storage Power Stations to the Grid" (GB/T36547-2024) was released in May this year and will be officially implemented on December 1 this year. The standard stipulates the power control, primary frequency regulation, inertia response, fault ride-through, operational adaptability, power quality, dispatching automation and communication of electrochemical energy storage power stations.

Taking power control as an example, power control is the basic function of electrochemical energy storage power stations. The specification stipulates that the charge and discharge response time of electrochemical energy storage power stations during local control shall not exceed 500ms, the charge and discharge adjustment time shall not exceed 2s, and the active power control deviation shall not exceed ±1% of the rated power. The power factor of the grid-connected point of the electrochemical energy storage power station should be continuously adjusted within the range of 0.9 (leading) to 0.9 (lagging).

Primary frequency regulation is a "must-have" configuration for energy storage on the power supply side and the grid side. The specification stipulates that the primary frequency regulation time shall not exceed 4s. When stability is achieved, the active power control deviation shall not exceed ±1% of the rated power.

At present, most regions in China require energy storage power stations that accept grid dispatch to carry out grid connection testing. By strengthening grid connection testing, the support and regulation capabilities of energy storage for the grid are improved. At the same time, it forces energy storage equipment manufacturers to improve equipment performance, standardize industry chaos, and promote the overall improvement of the industry's technical level.

Taking Jiangsu Province as an example, the scale of electrochemical energy storage projects in the province has jumped to the first place in the country, and the cumulative installed capacity of new energy storage has exceeded 5.4 million kW, a year-on-year increase of 10 times. During the peak summer period, the peak was achieved through centralized call-up, effectively filling the power gap during the peak summer period. Grid connection detection is the key to achieving efficient support for energy storage power stations in Jiangsu Province. The Jiangsu Provincial Development and Reform Commission issued the "Several Measures on Accelerating the High-quality Development of New Energy Storage in Our Province", requiring grid connection commissioning and acceptance work, and at the same time proposed that independent energy storage projects should be tested for grid connection performance every year for the first three years before being put into operation, and the whole station should be tested every year for three years to ensure that the operation time and availability of the energy storage power station meet the grid connection needs.

Grid-connected testing ensures that the energy storage power station can operate safely, stably, continuously and efficiently after being connected to the grid. At the same time, in the face of the development needs of new power systems under the new situation, especially the development of new technologies such as grid-connected energy storage, grid-connected testing also needs to constantly adapt to the development needs of new technologies to better serve the efficient and stable operation of new power systems.